New CT and MRI research suggests that opportunistic AI evaluation of vertebral bone mineral density (vBMD) on non-contrast chest CT may help identify individuals at risk for accelerated brain aging.
For the study, a secondary analysis of the prospective Multi-Ethnic Study of Atherosclerosis (MESA), researchers reviewed deep learning segmentation BMD assessments from chest CT and cognitive testing data for 715 study participants (median age of 69) as well as brain MRI data in 405 participants. There was no baseline evidence of cardiovascular disease, prior dementia or stroke for any of the cohort participants, according to the study, which was recently published in Radiology.
While the study authors did not see an overall association between lower baseline BMD and an increased rate of white matter hyperintensity (WMH) progression, the researchers pointed out significant regional associations with a 12.8 percent annual increase in WMH accumulation in the corpus callosum and a .0048 SD annual decline of fractional anisotropy (FA) in the anterior limb of the internal capsule (ALIC).
“The regional specificity of these associations offers insight into underlying mechanisms. The corpus callosum, ALIC, and fornix appear particularly susceptible, exhibiting associations with both FA decline and WMH progression. This is consistent with established WM vulnerability hierarchies where thinly myelinated association fibers and structures with elevated metabolic demands are prone to earlier age-related deterioration,” explained lead study author Sara Momtazmanesh, MD, who is affiliated with the Department of Radiology and Radiologic Sciences at Johns Hopkins University in Baltimore, and colleagues.
Is There a Stronger Link Between Vertebral Bone Mineral Density and White Matter Hyperintensity in Patients with Diabetes?
The association between lower vBMD and WMH was significantly pronounced in patients with diabetes. The study authors noted a nearly five percent faster accumulation of WMH among those with lower vBMD and diabetes in comparison to those without diabetes.
“Diabetes showed suggestive heterogeneity with stronger vBMD–WMH associations among participants with diabetes. This pattern is biologically plausible given diabetes-related endothelial dysfunction and chronic inflammation, which may increase susceptibility to WM injury and accentuate links between skeletal health and cerebral small vessel disease,” posited Momtazmanesh and colleagues.
Three Key Takeaways
• Chest CT may offer an opportunistic window into brain aging risk. In this MESA secondary analysis of 715 adults without baseline cardiovascular disease, dementia or stroke, AI-derived lower vertebral BMD on non-contrast chest CT was linked to faster cognitive decline. Each 0.1 g/cm³ lower baseline vBMD corresponded to a 0.025 SD faster annual decline in global cognitive composite score and a 0.32 percent faster annual decline in CASI score.
• White matter effects were regional, not global. Lower vBMD was not associated with overall WMH progression. However, it was associated with a 12.8 percent annual increase in WMH accumulation in the corpus callosum and faster fractional anisotropy decline in the anterior limb of the internal capsule. The corpus callosum, ALIC and fornix appeared most vulnerable so these regions may merit closer attention on follow-up brain MRI.
• Diabetes may amplify the association between WMH and lower vBMD. WMH accumulated nearly 5 percent faster in participants with both lower vBMD and diabetes, a finding that may be attributable to endothelial dysfunction and chronic inflammation, according to the study authors.
Does Declining Vertebral Bone Mineral Density Trigger Increased Cognitive Decline?
The researchers also found that for each 0.1 g/cm3 decline in baseline vBMD, there was a corresponding 0.025 standard deviation (SD) faster annual decline in global cognitive composite (GCC) score as well as a 0.32 percent faster annual decline in the Cognitive Abilities Screening Instrument (CASI).
“(Vertebral bone mineral density) associations with global cognition (CASI and GCC) were stronger among participants with lower triglycerides, possibly reflecting greater detectability in metabolically vulnerable states. Higher late-life triglycerides have been linked to lower dementia risk,” noted Momtazmanesh and colleagues.
Final Notes
(Editor’s note: For related content, see “Emerging CT Research Suggests Possible Correlation Between Subclinical Emphysema and Vertebral Bone Loss,” “Skeletal Muscle Loss and Dementia: What Emerging MRI Research Reveals” and “Can Biomechanical CT Have an Impact in Opportunistic Screening for Osteoporosis?”)
In regard to study limitations, the authors acknowledged the observational study design and the possibility of residual confounding factors that may have affected results. The researchers also noted the lack of assessment for inflammatory mediators and bone marrow adiposity, and use of a CT-based vBMD assessment research protocol that requires further validation before broader use in clinical setting.
